The present disclosure relates to a lens barrel that expands and contracts between a collapsed state and a photographing state, and relates to the technical field of an imaging apparatus provided with the lens barrel.
Of various imaging apparatuses such as a video camera or a still camera, there is a so-called collapsible-type imaging apparatus (for example, refer to Japanese Unexamined Patent Application Publication No. 2008-3272) in which a lens barrel is provided to freely expand and contract. A photographic optical system containing various optical components and optical elements such as a lens group is disposed in the inner portion of the lens barrel. The lens barrel can be stored in an apparatus body while not photographing; and a zoom ratio can be changed by extending the lens barrel from the apparatus body while photographing.
During usage, such as starting photography, the lens barrel is extended and transitions from the collapsed state to the photographing state. During non-usage, such as ending photography, the lens barrel is contracted and transitions from the photographing state to the collapsed state.
The collapsible-type imaging apparatus is provided with a plurality of annular barrels, and the lens barrel expands and contracts by moving in an optical axis direction while a predetermined barrel is rotated in a direction around the optical axis by a drive force of an actuator.
Such an imaging apparatus is capable of achieving both miniaturization (thinning) while not photographing and secured favorable optical performance while photographing due to the provision of the collapsible-type lens barrel.
In a collapsible-type lens barrel such as the one described above, a cam follower which is provided on a predetermined barrel is engaged with a cam groove, which is formed in another barrel and is inclined in relation to the optical axis, to slide freely. The lens barrel is moved in the optical axis direction by the cam follower of the barrel that is rotated by the drive force of the actuator sliding in the cam groove.
In the imaging apparatus including a collapsible-type lens barrel disclosed in Japanese Unexamined Patent Application Publication No. 2008-3272, the cam follower is prevented from detaching from the cam groove when a load is applied to the lens barrel by forming an escape path in the cam groove and ensuring that the cam follower engages with the escape path when a load is applied to the lens barrel in the optical axis direction.
As described above, in the collapsible-type lens barrel, since a configuration is adopted in which the cam follower is engaged with the cam groove to slide freely and a predetermined barrel is moved in the optical axis direction while rotating, the cam groove is inclined by a predetermined angle in relation to the optical axis.